Granted Patent B1

US 8,797,664 · App. 13/726,007 · Granted Aug 5, 2014

Abstract

Claims (43)

1. A disk drive comprising:

a disk for storing data;

an actuator arm;

a head connected to the actuator arm for reading data from the disk and for writing data on the disk;

a piezoelectric (PZT) actuator located between the actuator arm and the head for positioning the head over the disk; and

a controller configured to:

inject a test signal into the PZT actuator;

receive a position signal indicating a position of the head over the disk resulting from the test signal;

generate a test compensation signal based on the received position signal; and

determine a polarity of the PZT actuator based on a phase of the generated test compensation signal.

2. The disk drive of claim 1 , wherein the disk drive further comprises a non-volatile memory (NVM) for storing data, and wherein the controller is further configured to:

store the determined polarity of the PZT actuator in the NVM; and

control the PZT actuator during operation of the disk drive in accordance with the polarity stored in the NVM.

3. The disk drive of claim 1 , wherein the controller is further configured to determine the polarity of the PZT actuator by comparing the phase of the generated test compensation signal with a threshold phase.

4. The disk drive of claim 3 , wherein the controller is further configured to determine that the polarity of the PZT actuator is opposite from a default polarity if the phase of the generated test compensation signal differs by more than a predetermined amount from the threshold phase.

5. The disk drive of claim 4 , wherein the threshold phase is approximately 90 degrees from a default phase corresponding to the default polarity.

6. The disk drive of claim 1 , wherein the controller is configured to determine the polarity of the PZT actuator during a manufacturing process of the disk drive.

7. The disk drive of claim 1 , wherein the controller is configured to determine the polarity of the PZT actuator each time the disk drive is powered-up.

8. The disk drive of claim 1 , wherein the controller is configured to determine the polarity of the PZT actuator as part of a PZT actuator failure analysis.

9. A method for determining a polarity of a piezoelectric (PZT) actuator of a disk drive, wherein the disk drive includes a disk for storing data, and a head for reading data from the disk and for writing data on the disk, the method comprising:

injecting a test signal into the PZT actuator;

receiving a position signal indicating a position of the head over the disk resulting from the test signal;

generating a test compensation signal based on the received position signal; and

determining the polarity of the PZT actuator based on a phase of the generated test compensation signal.

10. The method of claim 9 , wherein the disk drive includes a non-volatile memory (NVM) for storing data, and wherein the method further comprises:

storing the determined polarity of the PZT actuator in the NVM; and

controlling the PZT actuator during operation of the disk drive in accordance with the polarity stored in the NVM.

11. The method of claim 9 , further comprising determining the polarity of the PZT actuator by comparing the phase of the generated test compensation signal with a threshold phase.

12. The method of claim 11 , further comprising determining that the polarity of the PZT actuator is opposite from a default polarity if the phase of the generated test compensation signal differs by more than a predetermined amount from the threshold phase.

13. The method of claim 12 , wherein the threshold phase is approximately 90 degrees from a default phase corresponding to the default polarity.

14. The method of claim 9 , wherein the polarity of the PZT actuator is determined during a manufacturing process of the disk drive.

15. The method of claim 9 , wherein the polarity of the PZT actuator is determined each time the disk drive is powered-up.

16. The method of claim 9 , wherein the polarity of the PZT actuator is determined as part of a PZT actuator failure analysis.

17. A non-transitory computer-readable medium storing computer-executable instructions for determining a polarity of a piezoelectric (PZT) actuator of a disk drive, wherein the disk drive includes a disk for storing data, and a head for reading data from the disk and for writing data on the disk, and wherein when the computer-executable instructions are executed by a controller, the controller:

injects a test signal into the PZT actuator;

receives a position signal indicating a position of the head over the disk resulting from the test signal;

generates a test compensation signal based on the received position signal; and

determines the polarity of the PZT actuator based on a phase of the generated test compensation signal.

18. The non-transitory computer-readable medium of claim 17 , wherein the disk drive further includes a non-volatile memory (NVM) for storing data, and wherein when the computer-executable instructions are executed by the controller, the controller further:

stores the determined polarity of the PZT actuator in the NVM; and

controls the PZT actuator during operation of the disk drive in accordance with the polarity stored in the NVM.

19. The non-transitory computer-readable medium of claim 17 , wherein when the computer-executable instructions are executed by the controller, the controller determines the polarity of the PZT actuator by comparing the phase of the generated test compensation signal with a threshold phase.

20. The non-transitory computer-readable medium of claim 19 , wherein when the computer-executable instructions are executed by the controller, the controller determines that the polarity of the PZT actuator is opposite from a default polarity if the phase of the generated test compensation signal differs by more than a predetermined amount from the threshold phase.

Assignments (7)